皆伐对青藏高原东部银露梅种群生长与繁殖的影响

调查了青藏高原东部川西云杉原始林下优势灌木银露梅及其在皆伐7 a后迹地上的种群结构、生长与繁殖状况,并进行了对比研究.发现(1)皆伐迹地生境中的银露梅灌丛年龄结构、萌生株年龄结构、萌生株数大小结构和冠幅结构与原始林下相比均存在着较大的差异;(2)在皆伐生境中,与林下同龄的银露梅丛冠幅、基径总和以及株高总和均显著增加,皆伐显著促进了银露梅的无性萌生能力和结实数量的增加.综合分析表明,银露梅能有效适应迹地退化形成的阳性生境,因此可作为高海拔地区皆伐迹地植被恢复中先锋灌木种.图2表1参21     

沙地退化植被恢复过程中灌木发育对草本植物和土壤的影响

应用野外调查和室内分析方法,通过对科尔沁沙地沙丘固定和植被恢复过程中(流动、半流动、半固定和固定沙丘)灌丛内外草本植物的特征和土壤的理化性质分析,研究了灌丛的发育对草本植物和土壤的影响.结果表明,4种沙丘小叶锦鸡儿灌丛下植物的盖度、高度和密度显著高于灌丛外围,由灌丛内向灌丛外呈现出明显下降的趋势.通过差巴嘎蒿、小叶锦鸡儿和冷蒿3种灌丛内、外的理化性质的对比分析表明,沙地灌丛的形成对灌丛下土壤有机碳、全氮、全磷、有效氮和有效磷均有不同程度的富集作用,特别是对土壤有机碳和全氮有明显的富集作用,其大小顺序为小叶锦鸡儿>冷蒿>差巴嘎蒿;小叶锦鸡儿灌丛对全磷和有效磷的富集作用明显大于其它灌木.这些结果表明在沙丘植被恢复过程中灌丛的发育具有明显的"保种"作用和"肥岛"效应,促进了沙丘植物的侵入和土壤的进一步恢复.     

陕北采油区灌木枯落叶对油污土壤环境的改良效应

采集陕北石油污染区典型荒地土壤,分别以3种石油污染水平(轻度污染15g/kg,中度污染30g/kg,重度污染45g/kg)油土混合培养后,施入当地9种常见灌木枯落叶进行室内分解培养试验120d,检测不同灌木枯落叶对油污土壤生物化学性质的影响.结果表明:柠条、沙棘、紫穗槐、沙蒿和小叶女贞枯落叶可明显促进3种水平油污土壤微生物的生长和土壤呼吸.柽柳、柠条、花棒和踏榔枯落叶可明显促进3种水平油污土壤碱性磷酸酶和脱氢酶活性.柠条、沙蒿、踏榔、小叶女贞、花棒、柽柳和紫穗槐枯落叶可明显增加3种水平油污土壤有机碳和速效K含量.爬地柏、沙棘和花棒枯落叶可明显提高3种水平油污土壤Fe、Mn和Zn的有效性.综合而言,柠条和踏榔枯落叶对3种水平油污土壤均有明显改良效果,紫穗槐枯落叶对轻度油污土壤、小叶女贞枯落叶对中度油污土壤,柽柳和紫穗槐枯落叶对重度油污土壤也均有较明显的改良效果.     

我国北方荒漠化地区主要灌木种的物候学研究

采用中国科学院沙坡头沙漠试验研究站１９８７～１９９７年物候连续观测资料,研究了我国主要荒漠灌木种在该地区的物候学特征,并分析了与温度、降水、光照、风速等环境因子的相关性,结果表明,均温与光照是这些灌木主要物候期的主导因子。通过聚类分析确立了３个萌动期物候类型、３个展叶期物候类型和４个开花期物候类型。研究结果对荒漠化地区人工植被建设和生物多样性迁地保护具有重要的意义.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Impacts of de-icing salt pollution on urban road greenspace: a case study of Beijing

De-icing salt contamination of urban soil and greenspace has been a common issue of concern in many countries for years. In the 2009/2010 winter, Beijing experienced a contamination accident resulting from the overuse of deicing salt, reported as almost 30000 tons, which severely damaged urban vegetation alongside roadways. The methods of sampling and rating for both soil contamination and response of the plant populations were developed to rapidly assess this emergency environmental event. Results showed that the shrubs were more severely damaged than the arbors in terms of both degree and extent, as almost all of the surveyed shrubs were severely damaged from the salt contamination, while only about 1/4 of the recorded arbors were rated as ＂severely injured＂ according to the integral plant injury index. The rating of the injury level showed that the trees like Pinus bungeana, Sophora japonica, and the shrubs like Euonymus japonicus, Sabina vulgaris showed less tolerance to de-icing salt pollution. The patterns of vegetation damage demonstrated that the ever-green shrubs alongside roads and the deciduous arbors in the center of roads were most vulnerable to the salt damage.     

走进森林简

窗外的一缕清风,悄悄地从窗棂的缝隙挤进屋里,将飘逸的纱帘儿微微吹动。望着窗外的晨曦,揉了揉惺忪的眼睛,这一夜在不知不觉中来了,去了,又在雨云中飘走了。淅淅沥沥的小雨渐渐地停了,晨风微微袭来,稍比刚才大了许多。我悄悄溜出房屋,轻轻地推开栅栏,轻手蹑脚地走出随风舞动的农家小院,拐向一条小路。我小心翼翼地踏着那略显湿滑的石板,任露水浸湿那挽起的裤腿,沿着灌木草丛缓缓攀行……     

可观可食树——菲油果

菲油果（feijoa sellowiana）又名肥吉果、费约果、风楠，系统金忍受科菲油果属常绿灌木或小乔木，原产南美国家，20世纪30年代初传入日本，在全球亚热带气候温暖地区广泛种植。     

Effects of Glomus mosseae on the toxicity of heavy metals to Vicia faba

A glasshouse pot experiment was conducted to investigate effects of the arbuscular mycorrhizal fungus Glomus mosseae on the growth of Vicia faba and toxicity induced by heavy metals （HMs） （Cu, Zn, Pb and Cd） in a field soil contaminated by a mixture of these metals. There was also uninoculation treatment （NM） simultaneously. Mycorrhizal （GM） plants have significantly increased growth and tolerance to toxicity induced by heavy metals compared with NM plants. P uptake was significantly increased in GM plants. Mycorrhizal symbiosis reduced the transportation of HMs fi＇om root to shoot by immobilizing HMs in the mycorrhizal, shown by increasing the ratios of HMs from root to shoot. Oxidative stress, which can induce DNA damage, is an important mechanism of heavy metal toxicity. GM treatment decreased oxidative stress by intricating antioxidative systems such as peroxidases and non-enzymic systems including soluble protein. The DNA damage induced by heavy metals was detected using comet assay, which showed DNA damage in the plants was decreased by the GM treatment.     

我从山中来带着兰花草

这次出差路过大别山腹地一个国家级自然保护区,在这个季节,路边无论是高大的乔木还是低矮的灌木甚至是平时不为人所注意的野草,都尽量展示出生命中所具备的原始冲动,它们交织成一幅幅欣欣向荣的春山全景图,处处都张扬着春天的气息。